Effect of fish oil supplementation on the concentration of miRNA-122, FGF-21 and liver fibrosis in patients with NAFLD: Study protocol for a randomized, double-blind and placebo-controlled clinical trial.

BACKGROUND & AIMS: To date, no specific drugs are available for non-alcoholic fatty liver disease (NAFLD), though the effect of fish oil supplementation on improving fibrosis in patients with NAFLD has been evaluated. N-3 polyunsaturated fatty acids (n-3 PUFA) may modulate the concentration of microRNAs (miRNAs) and fibroblast growth factor (FGF)-21, which have been identified as non-invasive markers of liver fibrosis. The present study aims to evaluate whether n-3 PUFA supplementation can modulate miRNA-122 and FGF-21 and improve liver fibrosis and steatosis, measured by transient hepatic elastography (THE), in individuals with NAFLD. METHODS: A randomized, double-blind, placebo-controlled clinical trial will be conducted to evaluate the effect of 4 g/day supplementation of fish oil (2100 mg EPA and 924 mg DHA) in patients with NAFLD over a 6-month period. Fifty-two patients aged >19 years will be randomly assigned to either a placebo (olive oil) or treatment (fish oil) group. Anthropometric data, food intake, physical activity, body composition, resting energy expenditure (evaluated using indirect calorimetry), liver enzymes, platelets, lipids and glucose profile, inflammatory markers (such as C-reactive protein, neutrophil/lymphocyte, platelet/lymphocyte, and monocyte/lymphocyte ratios), miRNA-122 and FGF-21 concentration, and incorporation of fatty acids into the erythrocyte membrane (analyzed using gas chromatography) as well as the degree of liver fibrosis and steatosis assessed using THE (Fibroscan® Touch 502, Paris, France) and liver biomarkers Steato-Brazilian Longitudinal Study of Adult Health, Fatty Liver Index, NAFLD Fibrosis Score, Fibrosis-4 score, and FibroScan-AST score will be evaluated at the beginning and end of the treatment. Continuous variables with normal distribution will be compared between placebo and intervention groups using Student's T test for independent samples; continuous non-parametric variables will be compared using Dunn or Mann-Whitney test. Associations between categorical variables will be analyzed using the chi-square test, and within-group differences will be evaluated using the Wilcoxon signed-ranks test. The criterion for determining significance will be set at 5%. CONCLUSION: The present study protocol will investigate the supplementation of EPA-rich fish oil as an alternative treatment for NAFLD and its feasibility in affecting the concentration of miRNA-122 and FGF-21 markers. Its findings will offer valuable contributions to the literature. REGISTRATION: ReBEC number RBR-8dp876.